Along with fast development of communications technologies, as one mainstream technology for the third generation of mobile communications system, wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) has been in extensive research and use worldwide. High speed downlink packet access (High Speed Downlink Packet Access, HSDPA) is introduced in a Rel-5 version drawn up by the third generation partnership project (3rd Generation Partnership Project, 3GPP) so as to accelerate the downlink data transmission rate.
In HSDPA technology, a NodeB (NodeB) transmits data to a user equipment (User Equipment, UE) via a high speed downlink shared channel (High Speed Downlink Shared Channel, HS-DSCH) in physical layer, meanwhile transmits a control signaling associated with the HS-DSCH etc. via a high speed physical downlink shared control channel (High Speed Physical Downlink Shared Control Channel, HS-SCCH). Upon receiving the HS-SCCH, the UE uses control information carried thereon to perform demodulation, decoding and etc. on the HS-DSCH, then according to receiving status of the HS-SCCH and whether or not the HS-DSCH is decoded correctly, the UE generates acknowledgement (Acknowledgment, ACK)/negative acknowledgement (negative acknowledgement, NACK) information. Moreover, the UE also measures the downlink channel condition and generates a channel quality indicator (Channel Quality Indicator, CQI); if the current network has configured multiple-input multiple-output (Multiple-Input Multiple-Output, MIMO) for the UE, the UE also need to generate a pre-coding control indicator (Pre-coding Control Indicator, PCI). The UE carries ACK/NACK information, CQI information and PCI information (the UE need not to feed back a PCI until the network has configured MIMO) on a HS-DPCCH channel, and transmits it to a NodeB. The NodeB regards the feedback information by the UE as factors of service scheduling.
Feedback modes of CQI and PCI information are controlled by higher layer configuration parameters: where a CQI feedback cycle (k) and a CQI repetition factor (N_cqi_transmit) respectively control a CQI/PCI feedback cycle and repetitive transmitting times of the CQI/PCI within one cycle. Once the network has configured these parameters for the UE, the UE shall transmit the CQI/PCI according to the mode designated by the network and according to protocol.
The current protocol might result in certain problems. For example, there are no scheduling data for a UE over an relatively long time period, however, the UE still feeds back CQI periodically; and in fact, during the time period when the network does not schedule data for the UE, the reported CQI is of no value, only the latest CQI to scheduling data is valuable.